Al2O3基陶瓷及玻璃基底制备Ta-N薄膜微结构与电学特性的比较研究

在N2、Ar气氛中,采用反应直流磁控溅射法在Al2O3基陶瓷及玻璃基底上制备了Ta-N薄膜,并对各样品的形貌结构、化学组分及电学特性进行了比较分析研究。结果表明,沉积于Al2O3陶瓷及玻璃基底的Ta-N薄膜分别呈团簇状生长与层状紧密堆积生长;Al2O3陶瓷基底沉积的Ta-N为单相薄膜,而玻璃基底上的Ta-N薄膜,随N2、Ar流量比增加,呈单相向多相共存转变;薄膜表面形貌和微结构与基底材料的原始形貌和微结构紧密相关,这说明基底材料对薄膜的形成有重要的影响;N2、Ar流量比相同时,玻璃基底上沉积的Ta-N薄膜电性能优于Al2O3基陶瓷基底上沉积的Ta-N薄膜。     

电子束蒸发沉积重掺硅薄膜及其在低辐射玻璃上的应用

采用电子束蒸发法以普通玻璃为基板制备了重掺硅薄膜,通过SEM、EDS、透射光谱对其形貌、成分以及透射率进行了测试表征.进一步采用铝诱导低温晶化法在玻璃基板上沉积Al薄膜,对重掺硅薄膜进行铝诱导晶化.XRD测试、电学性能测试以及可见-红外光谱透射率测试结果表明,硅薄膜在温度为300℃以上出现了Si(111)的衍射峰,薄膜的导电性得到了提高,且具有较强的红外反射能力,表明在低辐射玻璃上具有一定的应用价值.同时采用电子束蒸发法制备了结构为glass/Si/Ag/Si的Ag基低辐射玻璃,通过光学性质测试和腐蚀情况观察结果表明硅薄膜具有保护低辐射薄膜的作用.     

压头曲率半径对硬质薄膜结合力划痕测量影响的比较研究

硬质薄膜的膜/基结合力是表征材料可靠性的重要特性参数。采用划痕法测试硬质薄膜的结合力时,有很多因素会影响到临界载荷Lc的判定,例如薄膜和基底的硬度、模量,薄膜的表面粗糙度等;此外,仪器机架刚度、划痕速率、压头的曲率半径等仪器的测量参数也会影响临界载荷Lc的判定。采用划痕测量法,研究了曲率半径为20μm,50μm和100μm的压头对单晶硅和304基底的亚微米类金刚石薄膜与基底的结合力测量的影响。研究结果显示:随着压头曲率半径的增加,2种材料的临界载荷也随之增大。     

合理使用划痕法及显微法测定TiN薄膜与基体结合力

采用反应磁控溅射的方法在TC4钛合金基板上制备了TiN薄膜,利用划痕法测试了TiN薄膜与基体之间的结合力,并结合薄膜硬度与显微法判断的临界载荷进行了对比分析。结果表明:单纯依靠划痕法判断临界载荷较为局限,结合显微法同时考虑硬度等力学性能共同判断临界载荷,是更为科学合理的办法。     

钛过镀层对类金刚石薄膜的膜基结合力以及摩擦学性能的影响

采用双弧磁过滤真空弧源,在钴铬合金基体上成功地沉积了Ti/DLC多层膜,其钛过渡层利用不同的负偏压来制备.利用纳米划痕法来评价薄膜的膜基结合力,类金刚石薄膜的摩擦性能在销盘式摩擦磨损试验机进行测试.划痕法的结果均表明,增加钛的过镀层后薄膜的结合状况得到明显的改善,纳米划痕法测试膜基结合力表明其临界载荷可达到740mN,摩擦磨损实验可以看出镀膜后的样品的摩擦系数均在0.1左右,DLC薄膜可极大地改善钴铬合金的摩擦学性能.     

不同基底上SiO2薄膜的显微结构和力学性能

用电子束蒸发技术在K9玻璃及两种不同取向的钇铝石榴石(Y₃Al₅O₁₂, 简称YAG)晶体上沉积了SiO₂薄膜, 采用X射线衍射仪和纳米划痕仪对薄膜显微结构和力学性能进行了研究。实验结果表明: 薄膜在K9 、YAG(100) 和YAG(111)基底上分别呈现非晶态和多晶态; 沉积在不同基底上的薄膜的弹性模量并无明显差异; SiO₂薄膜在K9和YAG基底上呈现不同的划痕破坏模式, 并且YAG晶体上薄膜的粘附失效临界附着力远远小于SiO₂薄膜与K9基底的附着力。本文从薄膜的结构和弹性模量两方面分析解释了不同基底上薄膜的力学行为。     

多种基底上溅射沉积ZnO薄膜的结构

在玻璃基底和四种硅基底上用反应式直流磁控溅射法制备了ＺｎＯ薄膜。用ＡＥＳ和ＸＲＤ对薄膜结构和组分进行测试,结果表明,五种基底上生长的ＺｎＯ薄膜在不同程度上都具有优良的纵均匀性、明显的ｃ轴择优取向和较高的结晶度,而硅基底上薄膜的结构普遍优于玻璃基底上沉积的薄膜。     

磁控溅射法制备NiZnCo铁氧体磁性薄膜的工艺研究

采用磁控溅射在硅晶基体上制备NiZnCo铁氧体磁性薄膜,研究了溅射功率对溅射(沉积)速率和微观形貌的影响规律:随着溅射功率由80W增大到150W,薄膜的沉积速率增大;薄膜却由整齐均匀分布的小颗粒状向片状结构变化,分布也不均匀,晶粒明显长大.由此确定最佳溅射功率为120 W,薄膜的微观形貌最理想,溅射(沉积)速率也很快.     

WC-Co硬质合金基体上高附着力金刚石薄膜的制备

采用微波等离子体化学气相沉积(CVD)法在WC-Co硬质合金基体上制备金刚石膜, 研究了TiN_x中间层的引入对金刚石薄膜质量及其附着性能的影响. 结果表明, 在酸浸蚀脱钴处理的基础上, 通过预沉积氮含量呈梯度变化的TiN_x中间过渡层, 可在硬质合金基体上制备出高质量的金刚石薄膜; 压痕法测试其临界载荷达1000N.     

TiO2薄膜的LPCVD法制备、表征及光催化性能

采用简单易行的低压化学气相沉积法(LPCVD)在GaAs、Si和玻璃衬底上沉积了TiO2薄膜,通过HRXRD、FESEM、EDS等手段对薄膜进行表征,结果表明基片对薄膜的晶相和微观形貌有明显的影响。薄膜的光催化实验结果显示,在可见光的照射下,分解甲基橙溶液时,砷化镓基和硅基TiO2薄膜表现出更强的光催化活性。并探讨了基片对薄膜晶相、微观形貌、光催化活性的影响。     

Oxygen-ion-assisted deposition of thin gold films

Thin gold films have been deposited on glass and silicon substrates using ion-assisted deposition techniques. The adhesion of the films to the substrates is assessed by a scratch test. Deposition assisted by 100 eV-1 keV oxygen ions yields highly adhesive films that can only be removed by damaging the substrate. Argon and hydrogen ions produce films with relatively poor adhesion. The results show that the reflectance of oxygen-assisted films is reduced by trapping of the oxygen in the gold but no bulk chemical or structural changes are detected. It is proposed that a thin stable layer of gold oxide is formed during film growth and diffuses into the substrate, providing a strong bond for subsequent film deposition. Highly adhesive films with bulk optical properties are deposited on glass and silicon using oxygen-ion assistance only to the point of continuous film formation.     

铝诱导晶化真空蒸镀多晶硅薄膜的研究

采用真空蒸镀的方法在玻璃衬底上沉积1层非晶硅薄膜,再通过铝诱导晶化的方法制备出晶粒分布较均匀、晶粒尺寸0.5～5μm、晶化率达到89%的多晶硅薄膜。研究了衬底距离、衬底温度、退火温度对薄膜表面形貌、晶粒尺寸和分布及晶化率的影响。结果表明适中的衬底距离下得到的薄膜晶粒分布均匀,表面平整度好,薄膜厚度较大。薄膜的晶化率随着衬底温度和退火温度的提高而增大;随着退火温度的进一步提高,薄膜的晶化率达到最大值然后降低。     

Stress in the components of a thin film silicon monoxide capacitor and its relationship to dielectric loss

The cantilevered substrate technique has been used to measure the stress in aluminium and silicon monoxide films deposited in sequence on glass substrates. The stress is compressive in aluminium and tensile in silicon monoxide although the latter may be changed by prior exposure of the aluminium film to atmosphere.Electrical measurements were made on capacitors fabricated during the stress experiments. These showed that a definite relation existed between the dielectric loss and the stress.Possible reasons are suggested for these results.     

Chemical vapor deposition of aluminum from methylpyrrolidine alane complex

Chemical vapor deposition of aluminum from a recently developed precursor, methylpyrrolidine alane complex, has been studied. Aluminum films deposited on conducting surfaces (titanium nitride, copper, gold), but not on insulating surfaces (silicon, silicon dioxide, glass) at low substrate temperatures, showing deposition selectivity, while the deposition selectivity was lost at high substrate temperatures (> 210 °C). Al deposition rates on TiN and Cu were very close, but much higher than on Au. Deposition rates on all conducting substrates increased with the temperature and reached maximum at 180 °C. Al films deposited on as-sputtered TiN or Cu have no preferred orientations. Al–Au alloys and intermetallics were observed in the films deposited on Au. Surface morphology observation revealed that the film growth on TiN or Cu is different from that on Au. The surface roughness of Al films increased with the deposition time or the film thickness.     

N-type crystalline silicon films free of amorphous silicon deposited on glass by HCl addition using hot wire chemical vapour deposition

Since n-type crystalline silicon films have the electric property much better than those of hydrogenated amorphous and microcrystalline silicon films, they can enhance the performance of advanced electronic devices such as solar cells and thin film transistors (TFTs). Since the formation of amorphous silicon is unavoidable in the low temperature deposition of microcrystalline silicon on a glass substrate at temperatures less than 550 degrees C in the plasma-enhanced chemical vapour deposition and hot wire chemical vapour deposition (HWCVD), crystalline silicon films have not been deposited directly on a glass substrate but fabricated by the post treatment of amorphous silicon films. In this work, by adding the HCl gas, amorphous silicon-free n-type crystalline silicon films could be deposited directly on a glass substrate by HWCVD. The resistivity of the n-type crystalline silicon film for the flow rate ratio of [HCl]/[SiH4] = 7.5 and [PH3]/[SiH4] = 0.042 was 5.31 x 10(-4) ohms cm, which is comparable to the resistivity 1.23 x 10(-3) ohms cm of films prepared by thermal annealing of amorphous silicon films. The absence of amorphous silicon in the film could be confirmed by high resolution transmission electron microscopy.     

Growth of polycrystalline-silicon thin films on glass

Borosilicate glass was chosen as a substrate for solution growth of silicon due to its potential role as the superstrate of a solar module. The deposition of polycrystalline silicon on glass from solutions containing aluminium or magnesium is reported. Island growth was usually obtained when the deposition temperature was below 750 C. Large-grain, continuous, silicon thin films with an area of 10 cm² were grown on glass substrates at temperatures around the softening points of the glass. The growth of silicon on glass can be explained on the basis that the presence of aluminium and magnesium in the solution reduces SiO₂ and exposes silicon on the glass surface. The silicon-rich surface improves the wetting of the glass by the solution and acts as seeding sites for silicon nucleation. The periodic-regrowth technique was used to improve the quality of the polycrystalline silicon thin films deposited on the glass substrates. Periodic repetition of the melt-back and regrowth procedures removed the small-grained crystals, suppressed the rapid growth of crystals perpendicular to the substrate and enhanced the growth of slower-growing crystals in the lateral direction. This process markedly improved the smoothness, the grain size, the crystal quality and the (1 1 1) preferred orientation of the silicon thin films. Diode characteristics were obtained for p-n junction devices made on these polycrystalline silicon thin films deposited on glass substrates.     

Phosphorous and boron doping of nc-Si:H thin films deposited on plastic substrates at 150 °C by Hot-Wire Chemical Vapor Deposition

Gas-phase phosphorous and boron doping of hydrogenated nanocrystalline thin films deposited by HWCVD at a substrate temperature of 150 °C on flexible-plastic (polyethylene naphthalate, polyimide) and rigid-glass substrates is reported. The influence of the substrate, hydrogen dilution, dopant concentration and film thickness on the structural and electrical properties of the films was investigated. The dark conductivity of B- and P-doped films (σ_d = 2.8 S/cm and 4.7 S/cm, respectively) deposited on plastic was found to be somewhat higher than that found in similar films deposited on glass. n- and p-type films with thickness below ∼ 50 nm have values of crystalline fraction, activation energy and dark conductivity typical of doped hydrogenated amorphous silicon. This effect is observed both on glass and on plastic substrates.     

Deposition and modification of titanium dioxide thin films by filtered arc deposition

Thin films of titanium dioxide have been deposited on glass substrates and conducting (100) silicon wafers by filtered arc deposition (FAD). The influence of the depositing Ti⁻ energy, substrate types and substrate temperature on the structure, density, mechanical and optical properties have been investigated. The results of X-ray diffraction (XRD) showed that with increasing substrate bias, the film structure on silicon substrates changes from anatase to amorphous and then to rutile phase without auxiliary heating, the transition to rutile occurring at a depositing particle energy of about 100 eV. However, in the case of the glass substrate, no changes in the structure and optical properties were observed with increasing substrate bias. The optical properties over the range of 300–800 nm were measured using spectroscopic elliosometery, and found to be strongly dependent on the substrate bias, film density and substrate type. The refractive index values of the amorphous, anatase and rutile films on Si were found to be 2.56, 2.62 and 2.72 at a wavelength of 550 nm, respectively. The hardness and elastic modulus of the films were found to be strongly dependent on the film density. Measurements of the mechanical properties and stress also confirmed the structural transitions. The hardness and elastic modulus range of TiO₂ films were found to be between 10–18 and 140–225 GPa, respectively. The compressive stress was found to vary from 0.7 to 2.6 GPa over the substrate bias range studied. The composition of the film was measured to be stoichiometric and no change was observed with increasing substrate bias. The density of the film varied with change in the substrate bias, and the density ranged between 3.62 and 4.09 g/cm³.     

Structure of polycrystalline silicon films deposited at low temperature by plasma CVD on substrates exposed to different plasma

Polycrystalline silicon (poly-Si) films were deposited on glass substrates (corning 7059) at 300°C by a plasma enhanced chemical vapor deposition (PECVD) from a SiH₄/SiF₄ mixture. All poly-Si films were prepared under the same deposition conditions on the substrates subjected to nitrogen, hydrogen and/or CF₄ plasma with different gas pressures, just before deposition of the poly-Si films. Effects of such pretreatments for substrates on the structural properties of the resultant poly-Si films have been investigated. The Si film deposited on the substrates without any pretreatments was amorphous. However, formation of a strong 〈110〉 preferentially oriented poly-Si with improved crystallinity was obtained for the films deposited on the glass substrate after plasma pretreatments, which exhibit smoother surfaces. This result was interpreted in terms of a removal of weak Si–Si bonds during nucleation and the subsequent grain growth.     

Rotation Speed-Induced Uniaxial In-Plane Anisotropy in Thin Films Deposited Onto a Rotating Substrate

The Rotating Cryostat system consists of a rapidly rotating, liquid-nitrogen-cooled drum, around which a substrate can be placed. The possibility of using multiport sources gives the system wide capabilities for producing new materials. The effects of various rotation speeds of 1900, 1500, 1000, 500, and 0 rpm on the magnetic properties of thin iron films deposited on different (glass, silicon, and Kapton) substrates from a resistively heated evaporation source and a dc sputtering source have been investigated. Magnetic measurement showed that the films have an in-plane magnetic anisotropy for all films deposited at high speeds on all types of substrates and the degree of magnetic anisotropy decreased with decreasing rotational speed for flexible Kapton substrate. While the glass and silicon substrates was stationary, in-plane magnetic anisotropy of the films dropped down to zero. The films deposited on Kapton showed the rotational-speed-dependent magnetic properties. Estimation of magnetic anisotropy confirms in-plane anisotropy in the films. Furthermore, as expected for all iron films no magnetic anisotropy perpendicular to film plane was observed irrespective of rotation speed and type of substrate used.